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A Duncan Seawall Process to Reinforce a Failing Seawall

by Scott Myers

Duncan Seawall's team of experts and years of experience when reinforcing a failing seawall and ensuring it stands for years to come.


Related Blog: 4 Reasons Seawalls Fail and How to Prevent It

Depressions and cracking
, located in the concrete behind a seawall, prompted a new customer to reach out to us at Duncan Seawall, Dock & Boat Lift, LLC. There are visual clues when a seawall needs immediate attention.

  • Depressions Behind the Wall
  • Horizontal and/or Longitudinal Cracks
  • Caps and Top of Seawall Panels Leaning (In or Out)


Why a Coastal Engineer is Enlisted for Design?

Hardpan soil, or a hardened layer of earth, is found under the waters of this customer's South Siesta property. For this particular seawall project, and many others, it is important to enlist a coastal engineer to come up with the best design of a vinyl seawall that will be constructed in front of the existing, concrete wall. It is vital that the seawall design accommodates for lateral movement.


Why a Vinyl Seawall is the Preferred Solution?

Since our customer has already invested in a concrete seawall, a vinyl seawall is an efficient solution to reinforce this failing, concrete barrier. Vinyl seawalls are now becoming a preferred solution offering lower cost, high sustainability, and ease of installation.


Understanding when and why we recommend vinyl seawalls will help you have the knowledge to understand the benefits behind our recommendation. One such benefit from vinyl seawalls is the interlocking design that lowers the possibility of panel separation and erosion. Another great feature of vinyl seawalls is the resistance to rust. With regular inspection and maintenance, a vinyl seawall may last more than 20 years. 


Why the Flat Panel Versus the Corrugated Panel?

For our customer's project, we are using a Truline® Panel that gives the flat panel facade with fillable voids. This vinyl seawall will be a sturdy, solid barrier once it's completed.

There are two types of vinyl panels: corrugated and flat. Corrugated panels are used for a multitude of construction projects, but the flat panels are more aesthetically preferred for seawall construction.


Why Truline® Panels? 

We are using the Truline® Panel because it eliminates the problem of not having proper penetration into the sand table. Once the installation of the vinyl sheet piles is completed, it's time to secure and fill-in the voids with concrete to form a solid, steel-reinforced, concrete wall.

  • All sand and sediment are removed down to the rock layer.
  • Steel pins are driven into the rock layer, within each void, at depths specified by the engineer.
    • These steel pins create a toe with the bottom of the wall to secure the bottom of the wall from moving outwards. 
  • The voids are filled with 5,000 psi concrete.


Creating the Seawall Cap and Completing the Project

For this customer, we used seven (7) of #5 reinforcing steel, and our steel stirrups were placed at 18" on center, maximum. Once the formwork, or mold, is up, the concrete is poured or placed.

Once the concrete has been placed, it is left to cure for 24-hours. After the initial 24-hour cure-time, the side formwork is removed. After 48-hours, the bottom formwork is removed. 

Once all formwork has been removed, all edges are tooled for a rounded-finish. Finally, it's time for backfill to prepare for sod and landscaping. 


Why Duncan Seawall, Dock & Boat Lift, LLC?

Since 1979, the Duncan team has built a reputation for quality marine construction. We are Southwest Florida's major marine contractor in the residential sector, and we gladly work with projects of any size for our fellow residents or commercial businesses. We take pride in helping our customers understand the entire process, and we have a dedicated team to take care of the initial permitting requirements to the completed project cleanup.


If you have a seawall, or you would like to have one constructed, know the impacts of a failed seawall. The Duncan team is here no matter the reason, and we make it our business to do every job right, no matter how big or how small. At Duncan Seawall, Dock & Boat Lift, LLC, we are here for you. 

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